1. Field of the Invention
The present invention relates to a two-sided or multiple copy image forming apparatus.
2. Description of the Prior Art
Hitherto, in the case of synthesizing two images on a sheet of transfer paper, one original paper is set on the original plate and copied, thereafter it is removed and another original paper has to be again set on the original plate and copied again by a manual operation. Therefore, there are drawbacks such that it takes time for the exchange of originals and for copying by manual operation and it is possible to erroneously insert paper in the wrong direction for copying by manual operation.
On one hand, in the case where att least one original includes unnecessary portions, this original has to be copied after the unnecessary portions were manually cut or covered using paper or the like, so that it is very troublesome.
In addition, in case of changing the position of the image on the transfer paper, it is difficult to set the original at the necessary position, resulting in working inefficiency and causing failure of the apparatus.
In the case of synthesizing two images on a sheet of transfer paper with variable magnifications, respectively, one original is set on the original plate and copied with a desired magnification, thereafter it is removed and another original has to be set on the original plate and copied again by manual operation. Thus, there are drawbacks such that it takes time for the exchange of originals and for manual operation and it is possible to erroneously insert a paper in the wrong direction upon manual operation.
On one hand, in recent years, the function of making a blank space for binding the margin has been considered. However, according to this function, such a blank can be made on only either one side (the side of the front edge of the recording paper or the side of the rear edge thereof) by a single operation. Therefore, in case of recording two images on both front and back surfaces of one recording paper, there is a drawback such that the blank spaces for the binding margins will have been made to the left on the front surface and to the right on the back surface of the recording paper and in the opposite directions when the recorded image is seen from the direction of the other surfaces of the paper.
In case of copying originals of a book or the like using the serial page copy function by which the right and left pages are individually read, a black frame is caused on the corner sides of the images; therefore, to prevent such a black frame, a masking function using the size of the original as a reference has been provided. However, either the serial page copy function or the masking function has to be individually selected, causing drawbacks such as the omission of the selection or non-selection of the masking function, and the delay in pressing the masking function selection key, and the deterioration of efficiency and picture quality.
On the other hand, image forming apparatus have been developed in which two images are synthesized and recorded on one side of one recording paper or recorded on the front and back surfaces of one recording paper.
It is also known where the image shifting operation is performed, to make the binding margin in such an apparatus. For this purpose, the operator selects the image shifting function if necessary and releases this function if it is unnecessary. However, the operator can have a lapse of judgement or forget the selection or release of the image shifting function, resulting in a case of miscopying. In addition, as well as the selection of the synthetic recording mode or the two-sided recording mode, the image shifting operation has to be selected or released every time, so that the operating efficiency is poor.